Effects of cold plasma or electromagnetic field treatment on growth of bioluminescent fungus panellus stipticus

Abstract

Numerous studies on cold plasma (CP) effects on germination of fungal spores, viability and further colonies formation report detoxifying effects and reduction of mycotoxins, degrading and dying spores, inhibited mycelium growth. Low frequency electromagnetic field (EMF) was also assessed as agent degrading fungi, though there were species dependent exceptions, when exposure had positive impact. Wood decaying fungi deserve greater attention because after exposure to different treatments some species produce secondary metabolites having potential for wide application in future technologies (e.g. luciferin produced by bioluminescent species). The aim of this study was to evaluate effects of air CP irradiation and strong EMF on early growth of wood decaying bioluminescent fungus Panellus stipticus (colony diameter across the axis crossing the center of the sowing spot and colony surface area), and bioluminescence of mycelium. Spores of P. stipticus were injected on glass microscope slide and were treated for different durations (0.5, 1 or 3 min.) with a scalable dielectric barrier discharge (DBD) device having a plasma irradiation area of 4 x 4.38 cm2 (discharge voltage: 9.2 kV, 10 kHz; discharge current: 0.2 A, 2.17 W; power density: 3.1 W/cm2). For EML treatment spores were injected into a mini centrifugal plastic test-tube which was placed in the center of the induction coil, and treatment by electromagnetic field alternator (frequency, 100 kHz; electromagnetic field strength, 10 mT) was performed for 1 or 3 min. Spores were sown on Petri dishes filled with malt agar medium immediately after treatments and grown in a dark room at the air temperature around +13 oC for 3 weeks, periodically measuring the diameter and surface area of the colonies.[...]